Factors affecting the phytotoxicity and persistence of Group 2 herbicides in prairie soils

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Abstract

Advantages of Group 2 herbicides include low use rates, broad spectrum weed control
and low mammalian toxicity. However,Group 2 herbicides often persist in soil and cause
damage to subsequent crops in rotation. Phytotoxicity and persistence are the two parameters
that determine the potential damage that could occur from these herbicides. These parameters
are affected by soil properties, both chemical and physical, and by environmental factors.
Phytotoxicity is often increased and persistence extended by low soil organic matter contents.
If the compound is susceptible to hydrolysis, low pH can cause increased rates of dissipation
due to this chemical process. Microbial activity and the environmental factors that influence
decomposition also play a large role. Increased moisture and temperature typically result in
increased microbial activity and decreased persistence. Identifying the factors which are most
influential in the phytotoxicity and persistence of Group 2 herbicides is important in managing
crop rotations and reducing potential for crop damage.